Terrance Watanabe lost $189 million at Caesars Palace and the Rio in 2007, according to new court filings. The $189 million figure represented about 6 percent of all of Harrah's casino revenue in Las Vegas that year. In all, Watanabe gambled more than $800 million at Caesars Palace and Rio in 2007.
Because of these numbers people are calling Watanbe the biggest whale of all time in Las Vegas. While it is probably impossible to prove, it's hard to imagine anyone losing more than that in one year, although I guess it would be possible.
Watanabe is legendary around Vegas for gambling so much that he could cause Caesars Palace to have a profit or a loss on any given weekend based on how well he did at the tables.